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Aggregate / summarize multiple variables per group (e.g. sum, mean)
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Using the data.table package, which is fast (useful for larger datasets)
https://github.com/Rdatatable/data.table/wiki
library(data.table)
df2 <- setDT(df1)[, lapply(.SD, sum), by=.(year, month), .SDcols=c("x1","x2")]
setDF(df2) # convert back to dataframe
Using the plyr package
require(pl...
No submodule mapping found in .gitmodule for a path that's not a submodule
... it worked for me after having edited the .gitmodules file to change https:// links by git:// links
– Diwann
Jun 18 '13 at 12:24
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Best practices to handle routes for STI subclasses in rails
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I suggest you take a look at : https://stackoverflow.com/a/605172/445908, using this method will enable you to use "form_for".
ActiveRecord::Base#becomes
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Detecting iOS / Android Operating system
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If you're using React Js for your website, use https://www.npmjs.com/package/react-device-detect
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Bash function to find newest file matching pattern
...cut -d' ' -f2
For a more useful script, see the find-latest script here: https://github.com/l3x/helpers
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Creating default object from empty value in PHP?
... bool(false)
$res->success = (bool)0; // bool(false)
More infos:
https://www.php.net/manual/en/language.types.object.php#language.types.object.casting
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android pick images from gallery
... const val READ_EXTERNAL_STORAGE_REQUEST_CODE = 1001
}
}
Demo
https://github.com/PhanVanLinh/AndroidPickImage
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What is the difference between jQuery: text() and html() ?
...e.html">Link</a><b>hello</b>');
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<div id="div1"></div>
<div id="div2"></div>
Live demo on http://jsfiddle.net/hossain/sUTVg/
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How to remove outliers from a dataset
...moving outliers, and found this package (surprisingly called "outliers"!): https://cran.r-project.org/web/packages/outliers/outliers.pdf
if you go through it you see different ways of removing outliers and among them I found rm.outlier most convenient one to use and as it says in the link above:
"I...
How do you create a Swift Date object?
...y method.
A more elaborate example, which addresses both issues, is here: https://gist.github.com/algal/09b08515460b7bd229fa .
Update for Swift 5
extension Date {
init(_ dateString:String) {
let dateStringFormatter = DateFormatter()
dateStringFormatter.dateFormat = "yyyy-MM-...